474 
Glycyrrhizin  in  Licorice  Root.        j  ^jlfy  r'i92?arm' 
For  the  precipitation  I  dissolved  the  extract  from  5  g.  licorice 
in  50  g.  water.  I  consider  this  proportion,  1  +  9,  the  best.  If  the 
solution  is  more  dilute  there  is  danger  of  greater  losses  through  the 
solubility  in  more  water.  If  one  goes  under  this  proportion,  one  must 
necessarily  use  more  liquid  for  washing,  which  again  entails  more 
loss.  I  have  used  the  purification  recommended  by  Diehl,  because  it 
gives  good  results,  as  I  have  already  discussed  under  Haffner's 
method.  In  carrying  out  Diehl's  method,  I  have  already  mentioned 
that  his  ammonium  salt  is  notably  of  lighter  color  than  that  of  the 
impure  acid.  The  difference  is  easy  to  see.  It  is  also  important  to 
note  that  this  purification  does  not  seem  to  be  accompanied  by  any 
loss,  as  happens  with  Haffner's  method.  With  the  quantity  of  alco- 
hol I  use,  one  does  not  obtain  at  the  end  of  the  extraction  of  the  acid, 
a  perfectly  colorless  extract.  But  I  am  satisfied  that  70  cc.  alcohol  is 
sufficient,  after  having  convinced  myself  that  further  quantities  of 
liquid  leave,  after  evaporation,  a  hardly  weighable  residue.  This 
condition  is  accounted  for,  by  the  extraordinary  coloring  power  of 
the  impurities  of  the  glycyrhizic  acid.  By  evaporating  the  alcoholic 
solution,  and  determining  the  glycyrrhizic  acid  as  such,  and  not  as  a 
salt,  I  avoid  the  errors  of  many  of  the  other  methods,  which  convert 
the  sulphuric  or  hydrochloric  acid  which  is  not  washed  out  into  am- 
monium salt,  and  thereby  obtain  more  or  less  considerable  losses. 
I  consider  the  determination  of  the  glycyrrhizin  in  the  evapor- 
ated alcoholic  solution  more  exact  and  convenient  than  when  it  is 
weighed  in  a  weighing  bottle  on  a  filter  paper.  The  determination 
of  the  loss  which  I  give,  is  based  upon  the  explanation  given  in  the 
introduction.  I  can  draw  upon  the  large  number  of  experiments  made 
in  this  connection.  The  sum  of  the  two  individual  determinations 
gives  the  glycyrrhizin  content  of  the  licorice. 
By  several  glycyrrhizin  determinations  carried  out  by  my 
method,  I  obtained  9.00  +  1. 11  =  10. 1 1 ;  9.05  -f-  0.93  =  9.98;  9.31  + 
0.84  =  10.15;  9.4  +  0.92  =  10.32;  9.5  -f-  0.91  =  10.53  per  cent. 
[Note. — This  is  a  misprint  for  10.41  per  cent.  (P.  A.  H.)] 
The  method  proposed  by  me  takes  considerably  more  time  than 
the  majority  of  the  methods  hitherto  published.  I  attain,  however, 
by  my  method,  relatively  high  values,  with  a  considerably  higher  de- 
gree of  purity,  and  have  only  trifling  losses  of  glycyrrhizic  acid. 
